"We're looking at all avenues in the search," said Green. "We don't want to overlook any possibility. And this is just another tool in the search -- like using the aircraft yesterday."

Green said today's effort will move to Willamette River as Clackamas and Multnomah Sheriff's Offices will use side scanning sonar to search the water, especially near Sportcraft Marine and Clackamette Park in Oregon City, Meldrum Bar Park in Gladstone, and the Milwaukie boat ramp in Milwaukie.

Detectives are following up on the limited number of tips they received overnight, Green said. They have tracked Kline's credit and debit card activity, and he said there's been none since Friday afternoon at a gas station in Tualatin.

The sheriff's office will continue to follow up on tips received from the public, Green said, and continues to ask for the public to call in information.